• Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.

    If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.

    Enjoy.

Speedo Questions - S1 sorta

woodybap

Silver Level Sponsor
Thanks all. I will be back and working on the car next week. I will then try to provide more exacting details.
 

woodybap

Silver Level Sponsor
Back in town and here is the follow-up info on the speedo issue.

I compared various indicated speeds against both a radar setup and a GPS.

The speedo needle does not start to move until about 10 mph +/- 2 mph. In fact, almost all of the test measurements were off by 10 mph +/- 2 mph at 10, 20, 30, 40 & 50 mph indicated. So indicated of 10 was true of 19, 20 was 29, 30 was 39, 40 was 49 and 50 was true of 60. It was a little different in the midrange where an indicated of 35 was a true of 42 and an indicated of 37 was a true of 45.

The tires are P185/65R13. The speedo says 1020 on its face. There are no kinks in the cable. I do not know the gear ratio of the differential but doubt it is other than stock.

So, can this speedo be calibrated / adjusted / fixed or is it better to just let it be.

Next, the back of the speedo has a cable hanging down with an adjuster at the end. I have marked it with an “X” in the photos. It is not for the tripometer. That one works. This one just hangs down and, at present, twisting the cable end seems to do nothing. What is it?
 

Attachments

  • Back of Speedo 1 .jpg
    Back of Speedo 1 .jpg
    265.4 KB · Views: 18
  • Back of Speedo 2 .jpg
    Back of Speedo 2 .jpg
    299.2 KB · Views: 19

absunbeam

Platinum Level Sponsor
It's suppose to reset the tripometer, unscrew it and see if the cable turns when you turn the knob. Maybe broke or not engaged in the back.
 

alpine_64

Donation Time
Woody, jack the rear wheels up and turn the propshaft and count the revolutions vs wheels. See if you are getting more than 4 turns or less than 4 turns. ( more is a 4.22:1 diff less will be the 3.89:1)

That will tell if you have a mismatched Speedo.

As discussed earlier as well could also be a mismatch of the little speedo drive gears in the trans.

It is odd though that you are basically getting to 20mph before needle moves.
Is the needle steady?
 

65beam

Donation Time
The second cable is the cable to reset the trip odometer on a series 1 or 2. It comes down and turns under the dash waist roll and is clamped to the bracket that secures the steering column. What you have is an early speedometer housing that may have been altered to use the inner components of a later speedometer with an opening cut to allow the use of the later trip odometer reset arm. This housing does have the indicator light sockets and wiring for an early speedometer. Do you have a photo of the face of the speedometer? If it has two lights at the bottom of the face with one on the left labeled indicator and the one on the right labeled ignition then you have an early speedo face. What series car do you have?
 

woodybap

Silver Level Sponsor
The second cable is the cable to reset the trip odometer on a series 1 or 2. It comes down and turns under the dash waist roll and is clamped to the bracket that secures the steering column. What you have is an early speedometer housing that may have been altered to use the inner components of a later speedometer with an opening cut to allow the use of the later trip odometer reset arm. This housing does have the indicator light sockets and wiring for an early speedometer. Do you have a photo of the face of the speedometer? If it has two lights at the bottom of the face with one on the left labeled indicator and the one on the right labeled ignition then you have an early speedo face. What series car do you have?
Here is a photo of the face of the speedometer. It does have the 2 lights at the bottom. Also attached is another photo of the rear. The cable marked "Y" does hang down under the waist roll, is attached to the steering bracket. and turning it does reset to trip. The one marked "X" hangs down under and behind the dash and is the mystery cable. The body is mostly a Series I. The engine and some other parts are Series V.
 

Attachments

  • Front of Speedo 1.jpg
    Front of Speedo 1.jpg
    408.8 KB · Views: 20
  • Back of Speedo 2A .jpg
    Back of Speedo 2A .jpg
    302.2 KB · Views: 21

woodybap

Silver Level Sponsor
Woody, jack the rear wheels up and turn the propshaft and count the revolutions vs wheels. See if you are getting more than 4 turns or less than 4 turns. ( more is a 4.22:1 diff less will be the 3.89:1)

That will tell if you have a mismatched Speedo.

As discussed earlier as well could also be a mismatch of the little speedo drive gears in the trans.

It is odd though that you are basically getting to 20mph before needle moves.
Is the needle steady?
When I first got the car the needle swung wildly. That is why I replaced the cable. Now it holds steady just at the wrong speed. The speedometer needle does not move until the car reaches 10 MPH.
 

65beam

Donation Time
Here is a photo of the face of the speedometer. It does have the 2 lights at the bottom. Also attached is another photo of the rear. The cable marked "Y" does hang down under the waist roll, is attached to the steering bracket. and turning it does reset to trip. The one marked "X" hangs down under and behind the dash and is the mystery cable. The body is mostly a Series I. The engine and some other parts are Series V.

Woody
The one marked Y is the trip odometer reset for a series 4 or 5 speedometer. This was not part of a series 1 or 2 speedometer. The cable marked X is the cable for resetting the trip odometer of a series 1 or 2 so you probably have the guts of a late series Alpine installed in the series 1 speedometer housing. I'm basing this on this housing having the receptacles for the indicator and ignition lights. These lights are not used on later cars. It appears someone cut the opening for the late speedometer reset since this didn't exist on series 1 or 2. That would mean the series 1 reset cable ( X ) is there and attached to the housing but the inner cable itself could not be attached to anything if the guts are from a later series car. If the guts are from an unknown late car and the origin of the trans is unknown and you look at the charts of the speedometer then it's quite possible your speedometer doesn't read right because it's a mismatched later unit for your transmission that has been installed in the series 1 housing .
 
Last edited:

hartmandm

Moderator
Diamond Level Sponsor
The speedo might be a mismatch for the gearbox / differential ratio. But I think you have an internal speedo issue. If it was just a ratio mismatch and the speedo was behaving correctly, you should see a fixed percentage difference across all speeds. But you are seeing a 50% difference at 20 mph and a 20% difference at 50 mph. I'd open up the speedo, clean up the old grease and oil, and then re-lubricate it.

Use the articles in the 'Gauges' section here: http://wp.mhartman.net/home/cars/sunbeam/alpine/info

Once you get a good working speedo, you might still see a fixed percentage difference in speed readings due to some ratio mismatch.

Post photos if you disassemble the speedo and hopefully folks can figure out what you have inside. Worst case, a replacement speedo shouldn't be too hard to procure.

And what number do you see on the gauge face here? Is it SN6117/00?
upload_2020-2-17_11-24-3.png

Mike
 

hartmandm

Moderator
Diamond Level Sponsor
Looking more closely at the trip odometer area in your photo, it looks like some metal was cut out by hand. And the trip odometer has a yellow digit. A series 1 speedo would have a red digit. The series 4 & 5 speedos have yellow digits in the trip odometer. The opening probably had to be enlarged because the digits on the later speedo took up more space.

upload_2020-2-17_11-27-56.png


A series 1 speedo looks like this:
upload_2020-2-17_11-31-24.png

The series 4 standard speedo was 1000 revs per mile. Only a 2% difference from 1020.
The series 5 standard speedo was 1020 revs per mile, same as series 1.

So you can try to fix the speedo you have, or consider looking for a correct speedo (after you confirm the gearbox and differential you have).

There's a chance the speedo needle weight from an earlier speedometer is heavier than the speedo needle from a series 4 or 5 speedo. I think that could account for the speedo consistently reading low by 10 mph or so.

Mike
 

woodybap

Silver Level Sponsor
Looking more closely at the trip odometer area in your photo, it looks like some metal was cut out by hand. And the trip odometer has a yellow digit. A series 1 speedo would have a red digit. The series 4 & 5 speedos have yellow digits in the trip odometer. The opening probably had to be enlarged because the digits on the later speedo took up more space.

View attachment 18811


A series 1 speedo looks like this:
View attachment 18812

The series 4 standard speedo was 1000 revs per mile. Only a 2% difference from 1020.
The series 5 standard speedo was 1020 revs per mile, same as series 1.

So you can try to fix the speedo you have, or consider looking for a correct speedo (after you confirm the gearbox and differential you have).

There's a chance the speedo needle weight from an earlier speedometer is heavier than the speedo needle from a series 4 or 5 speedo. I think that could account for the speedo consistently reading low by 10 mph or so.

Mike

Great analysis Mike. The SN on the face is 6117/00.

Which gear do I use to check the ratio?

I will tinker with the speedo and report back. However my priority right now is locating and fixing the source of a clutch fluid leak.

Thanks to all.
 

Tom H

Platinum Level Sponsor
Woody,

The first question is does your speedo match your car. Take it for a drive and note how accurate the Odometer is. That will tell you if the speedo is matched correctly to your tranny and axle. The odometer is a GEARED measurement, so it's a very steady measure, and you can get a very accurate comparison driving over a couple miles, using highway markers or GPS. That will tell you if the speedo is correctly matched to your drivetrain. The MPH indication is a good bit "fuzzy" in its operation because it depends on a loose magnetic coupling between the cable driving a spinning magnet and a pivoting aluminum rotating cup attached to the needle with a spring return. The spring might be too strong or too weak, the magnetic coupling may be too weak, or the needle might be positioned off its cal position. But the odometer is a solid, geared, measurement and only the odometer can tell you solidly if the speedo is matched to your car. But like Mike suggested, your speedo may be a "bastardized" combination of different odometers.

Since your MPH needle does not move until the car is moving 10 MPH, I strongly suspect that the problem is the needle is incorrectly positioned on the pivot. There is a wire stop at zero on the speedo. During calibration (with the speedo out of its housing) that needle stop can be retracted and the pointer should rest naturally at a speed of about -5 MPH ( see the small white dot approximately where you would see -3 Kilometers/hr). If the needle is positioned on the pivot axle lower than that point it will take faster rotation of the cable to get it off the retractable needle stop.

As I said, first see if your speedo is matched to your car using the odometer check.

For more complete understanding of all this read this article on Mike's site, especially page 10:

http://mhartman.net/files/sunbeam/speedo.pdf

P.S. You asked "what gear" to use. What gear you are in does not matter. The speedo cable runs off a gear on the tailshaft of the tranny, so the rotation speed of the cable depends only on how fast the car is rolling, the rolling circumference of the tires, the axle ratio of the car, and the gear ratio of the speedo take -off (on the tailshaft). I do not know if the take-off ratio on the tranny is different between early Series and late Series trannys, but the take-off ratio IS different on an OD tranny.
 
Last edited:
Top